No. 0. 



THURBERIA ARKANSANA Beiitham. 



Plaul aniiiial. 



liootstock none. Roots very slender. 



Culms erect, simple or branching from the base, slender, commoidy !» to 18 

 inches high, sometimes depaujjerate, glabrous. 



Leaves of the stem 3 to 5; sheaths contiguous, glabrous or si)aringly villous, 

 the margin villous-ciliate; blade fiat, 1 to 4 inches long, 1 to 2 lines broad, flaccid, 

 scabroiis, and usually sparingly minutely villous-pubescent; ligule about ^ line 

 long, the ajjex narrowly fringed. 



Inflorescence a panicle at first partly .sheathed, finally pedunculate, 3 t(j 

 inches long; branches slender, seldom exceeding 1 inch in leugth; sjjikelets borne 

 singly on pedicels 1| lines long or shorter. 



Spikeleis linear, l^ to 3 lines long (exclusive of the awn), nearly terete, jointed 

 to the pedicel below the glumes. 



Glumes 3; first and second of equal leugth, similar, lanceolate, acute, green, 

 nerveless or obsoletely 3-nerved, scabrous-pubescent without, apices slightly sep- 

 arated; third (flowering) not green except the 3 nerves, glabrous, rather thick, 

 lauceolate, folded and compressed, awned on the back a little below the apex; apex 

 cleft half-way to the origin of the awn; awn slender, \ to i inch long, little twisted, 

 abruptly bent at the middle. 



Floiver single, hermaphrodite; rachilla prolonged above the flower (I) into 

 a minute filiform rudiment about \ line long, nakcl or surmounted by a minute 

 saile;"palet very thin, hyaline, narrowly linear, 2-nerved; lodicules 2, about i line 

 long; stamens 3, anther oblong, abt)ut i line long; stigmas cylindrical, on short 

 distant styles. 



Grain linear-oblong, remaining closed within the glumes, the spikelet disartic- 

 ulating below them. 



Plate IX; a, first (on the left) and second glumes; h, flowering glume and 

 flower. The riidimentary prolongation of the rachilla shown in h is usually twice 

 as long and is inserted at a point on the axis near the middle of the base of the 

 palet, not on the flowering glume, as shown in the figure. 



